Where can one acquire small (20-30) qty magnets suitable for use in Hall effect tach type applications? I'm thinking of the ultra-slim magnet splinters you see on floppy drive spindles and VCR head drums, about 2mmx1mmx0.5mm. After numerous attempts on my junkpile motors, I have not yet succeeded in salvaging one intact :)
In a related question, what are these normally attached with? I'm experimenting with motors with a max no-load speed of just under
5000rpm, under temperature conditions expected to range from -10 to +50 Celsius. I'm thinking an epoxy resin is probably best, but I'd be curious to hear what other people use.